Avoid Left Turns onto busy roads

[AlanOfTheBerg]

But what would Nascar and F1 drivers do? They can only turn left!

The "minimize lefts" idea has been brought up before. In general terms, though, as Waze collects data throughout the day, when people repeatedly get "stuck" in a left turn, Waze does "learn" that through calculation of segment-to-segment transit times. When that data is more complete, Waze routing automatically takes that into account and would, in those situations, mathematically "avoid" left turns, or any other kind of turn which is shown to be slower.

[AlanOfTheBerg]

How the heck does Waze know the time to turn? Is there an internal average speed or time value per-node-per-segment-per-direction now? I thought there was only averages per segment... How does it work then?

Waze tracks transit time from segment-to-segment (any segment to any segment at any junction) in 10 minute intervals all day long. This infos has been available for quite some time. So, yes, Waze should learn, as long as some people "get stuck" trying to turn a certain way, that it is incredibly slow to do so.

[AlanOfTheBerg]

In general terms, the answer to your question is "yes." That's how crowdsourced, or any other data-gathering system works. But, you could just restrict the "bad" turn.

[AndyPoms]

No automatic system can be as smart as the community. It's the local editor's job to identify problematic "left turns" and make sure there is a separate segment for that turn - if it's that bad, there should be a left turn separate lane for sure. Having a separate segment for the left turn and straigth ahead, waze will learn the left turn segment is slow and will then route people straight ahead.

I'd rather have the editors deciding if a left turn is safe and quick or dangerous by splitting the traffic information with relevant segments and then have the one algorithm taking care of it.

Waze knows the time to turn at intersections. Adding unnecessary turn lanes overly complicates the map and leads to other routing problems. A CM was recently removed for creating them (among other reasons).

[CBenson]

I like the avoid left turns onto major traffic routes idea as waze does NOT in fact learn to avoid such. Whenever I leave my apt waze always gives me a route that includes a left turn onto a major route. I occasionally play along and sit and sit waiting for a gap to make the turn in order to teach it that such a route is not adviseable during rush hour, but it has never given me an alternate route.

My experience is the opposite. Waze does clearly avoid some left turns. I frequently see URs where wazer indicates a routing problem precisely because waze didn't route through the left turn. I also play along a sit and wait for the gaps to make the turn and waze has learned to avoid the turn when I have done this.

No automatic system can be as smart as the community. It's the local editor's job to identify problematic "left turns" and make sure there is a separate segment for that turn - if it's that bad, there should be a left turn separate lane for sure. Having a separate segment for the left turn and straigth ahead, waze will learn the left turn segment is slow and will then route people straight ahead.

If the left turn is truly impractical or unsafe the turn can be restricted. I don't see the advantage a separate lane.

[CBenson]

Waze knows the time to turn at intersections. Adding unnecessary turn lanes overly complicates the map and leads to other routing problems. A CM was recently removed for creating them (among other reasons).

How the heck does Waze know the time to turn? Is there an internal average speed or time value per-node-per-segment-per-direction now? I thought there was only averages per segment... How does it work then?

Yes waze has stated that there is time value per-junction-per-segment-per-direction. Waze has said for quite some time that averages per segment that are available through WME are not the speed values used for the routing calculations.

[ChynnaBlue]

Waze tracks transit time from segment-to-segment (any segment to any segment at any junction) in 10 minute intervals all day long. This infos has been available for quite some time. So, yes, Waze should learn, as long as some people "get stuck" trying to turn a certain way, that it is incredibly slow to do so.

So does that mean we need to get stuck or forced into a dangerous situation in order for it to lean? Isn't there a better way? On my way home from work, Waze wants me to take a route with a stop sign at an unprotected left-hand turn across a busy 4 lane highway with an island between the lanes. I tried it once and ended up turning right and going another way. It could route me another way, but never does.

[cpragman]

Due to an accident on my main route, I hopped off the highway and took local streets near my house. Because I was only 5 miles from my house, I vaguely knew the roads, and had an idea of how to get home. I left waze on, mostly for amusement, and to see if it would suggest a better route.

It kept telling me to take alternate routes that all involved making multiple left turns onto busy roads. Each of the routes it offered was infinitestimally shorter than the route I already had decided to take, but all involved lots of left turns onto busy roads. Given that the highway I just got off was closed and all traffic diverted, I knew this was a bad idea, as I'd be stuck behind a long line of cars waiting to make that left turn.

It seemed to me like the waze routing system should know better than to build a route with a lot of left turns into busy traffic. Perhaps there is a way to insert a "bias" into the routing system, to avoid these sorts of turns (when possible) when building routes?

[daknife]

That would require marking the location of every traffic signal.

I like the avoid left turns onto major traffic routes idea as waze does NOT in fact learn to avoid such. Whenever I leave my apt waze always gives me a route that includes a left turn onto a major route. I occasionally play along and sit and sit waiting for a gap to make the turn in order to teach it that such a route is not adviseable during rush hour, but it has never given me an alternate route.

It doesn't even learn that going one block further west before attempting the turn will almost always get me turned faster due to a light managing the flow of traffic. No light needs to be plotted as traffic turning left there gets through every cycle (maybe two at most on really busy days), as to sitting for two, three or even four cycles of that same light while waiting to turn at the intersection Waze suggests.

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[davipt]

But what would Nascar and F1 drivers do? They can only turn left!

Why are mixing up proper car-racing with merry-go-round toys?